Skeleton structure such as aircraft fuselages



Nov. 13, 1928. 1,691,362

F. SIGRIST ET AL RCRAFT FUSELAGES SKELETON STRUCTURE sucn A5 A1 Filed June 1'5, 192'? Fly. .3.

FREORICK SaGIi ST',

SYDNEV AMM INVENTOR;

Minnay.

Patented Nov. 13, 1928.

UNITED STATES PATENT. orries.

renames: sienrs'r, or oxsnor'r, AND sYn 'EY CAMM, or noNe DITTON, ENGLAND.

SKELETON STRUCTURE soon AS AIIYRCR'AFT FosnLAGEs.

'Ap'plication filed June 15, 1927, Serial No. 198,951, and in Great Britain March 31, 1927 The present invention relates to skeleton structures and more particularly to metal constructed fuselages of air-craft in which connection it will hereinafter be described;

The primary objects of the invention are to provide an aircraft fuselage which is of simple, light and economical construction.

According to this invention the longrons of a fuselage and the interlongron struts or bracing members are formed of metal tubes which are squared or formed with flats at the joints or which are of square flattened or re tangular cross section througl out their length. The longrons and "the bracing members orstruts in either the vertical or horizontal bracing or both may be connected together at each joint by plates bolted or riveted to each of the adjacent mei bers.

Each side of the fuselage is preferably formed as a Warren, Pratt or like girder with the top and bottom longrons forming the top and bottom each oint formed by a pair oi? metal clam ing; plates bolted or rivets adjacent members andthe horizontal bays of the fuselage are formed by horizontal struts between the longerons braced by wires. These clamping plates are preferably connected to the struts or bracing members of the W'arren, Pratt or like girder by means of hollowrivets which are expanded in position and to the loiig'rons by a horizontal bolt passing therethrough and having an enlarged head which clamps a wiring plate or plates for the wire bracing against the side plates and is provided with means for engaging the horizontal struts of the horizontal bays. The wiring plate or plates may be provided with or comprise three lugs, two for the wire bra ingrin adjacent horizontal bays and one for the wire bracing in the plane of the aXes oi one set of the bracing members of the girders. The lugs of these wiring plates are set so that the line of each of the bracing wires passes through common point in the axis of the longr on thereby obviating; bending moments in the longrons.

In order that the invention may be more fully understood it will now be described with referenceto a practical example of construction which is illustrated in the accompanying drawings. These drawings illr rate joint between the top longron of a side of aeroplane fuselage of Warren booms thereof and with l to ea h of the members also the the longirder formation and the bracing of the girder. They illustrate method of engagement between grons and the horizontal struts.

Figure 1 is a side View as seen from the inside of the fuselage, the horizontal strut being omitted. v I

Figure 2 is a plaaand Figure 3 an end view looking from right to left of Figure 1. l

Referring now to these figures, 1 is the top longron of a side of a fuselage of "Warren girder formation and 2, 2 are struts extending between it and the lower lon rron which is not shown. The lons;**ons are fo med of steel tubes squaredor formed with flats at right angles so as to form a square in cross s ction with rounded. corners as shown in Figure 3. This section has b en found to possess the ad an arres of enab ing a simple, strong and light joint to be made. The top and bottom longrons on each side of thefuselage are braced bV square tubes 2, 2 of duralumin or s eel of the same cross section disposed in lVarreu a'irder formation so that eah side of the fuselage forms a arren girder. The inclination between each -oair of bracing members may be such that the lono'ron is stressed equally in each free length throughout its length whereby a structure of the greatest possible efiiciency is obtained. Each joint of the Warren girder is formed by a pair-of flat plates 3, r

3 of approximately triangular formation which clamp the three abutting members between them bymeans of two hollow rivets 4 through ea"h bracing member 2 and a bolt 5 through the axis of the lon gron. The rivets may be expanded into ferrules 6 placed in the holes of the clamping plates and bracing tubes. The bolt 5 has an enlarged head 7 on the inner side of the lVa-rren girder and wiring. plates compristhrce lugs, 8, 9.10 are mounted upon it so as to be clamped to the side of the longrron 1 between this head 7 and one of the joint plates 3. The enlarged head of each bolt is provided with a cup 11 to receive shaped. The horizontal struts may be formed of either square or. c rcular tubes of duralumin or steel having ball ended plugs of steel in the ends. In amodiiic-ation th horizontal struts may be cup ended and the bolts ball ended. The ends of the bracing tubes of the Warren girder are preferably cut at suitable angles to abut against each other and the longrons at the joints as shown'in Figure 1. The structure'is braced horizontally with the usual wires in the horizontal baysto take side thrust and diagonally in the plane of one set of,

plates, and that from this aspect the formation' of the structure from tubular members which are squared or of rectangular section at the joints, or which are of square, flattoned or rectangular cross section throughout their length, are particular instances of structures formed of tubular members provided withflats at the joints. I

It will also be noted that by the provision of flats at right angles on a. tubular member (such as a longrcn) at the joint or throughout its length, the end of an abutting member meeting it at right angles or inclined to it may be readily prepared to 'abut flush against it by a simple plane cut at the appropriate angle, thus securing the close abutmentadvisable to form a good joint without any difficult or lengthy shaping of the end of the abutting member.

e claim,

1. A skeleton structure such as a fuselage for aircraft, comprising side frames spaced apart, each side frame comprising tubular members provided with flats at the joints clamping plates engaging the flats, fastening means extendingthrough the plates and the tubular members meeting at a'joint, said fastening means comprising bolts having heads on the insides of the said frames pr0- vided with spherical bearing surfaces, horizontal struts between the opposite longrons having their ends formed with spherical bearing surfaces adapted to engage the spherical bearing surfaces of opposite bolt heads, and wire bracing between the said frames. 7 l

2. A skeleton structure such as a fuselage for aircraft, comprising side frames spaced apart, each side frame comprising tubular members provided with flats at the joints,

clamping plates engaging the flats, fastening means extending throughthe platesand the tubular members meeting at a joint, said fastening means comprising bolts having heads on the insides of the said frames provided with spherical bearing surfaces, horijoints.

' spherical zontal strutsbetween the opposite longrons having their ends formed with spherical bearing surfaces adapted to engage the spherical bearing surfaces of opposite bolt heads, wiring plates clamped between the bolt heads and the clamping plates on the insides of the side frames, and wire bracing between said side frames and connected with said wiring plates.

3. A skeleton structure comprising tubular longrous and interlongron struts or bracing members provided with flats at the joints, the said longrons-being continuous through the joints, clamping plates engaging the flats, and fastening means extending through the plates and the longerons and in- 1 terlongron struts or bracing members at the 4. A skeleton structure such as a fuselage for aircraft comprising side frames spaced apart, each side frame comprlsing upper and lower tubular longrons and mter lon'gron struts orbraclng members provided with flats at the joints, the said longrons being continuous through vthejoints, clamping plates engaging the flats, fastening means extending through the plates the longrons and the interlongron struts or bracing members, said fastening 4 means comprising insides of the side frames adapted to engage horizontal. struts between the opposite longerons, and horizontal struts engaged by said bolt heads.

5. A skeleton structure such as a fuselage:

bolts having heads on the for aircraft comprisingside frames spaced apart, eac'hside frame comprising upper and lower tubular longrons and interlongron struts or bracing members provided with flats at the joints, clamping plates engaging the flats, fastening means extending through the plates the long'rons and the interlongron struts or bracingmembers, said fastening means comprising bolts having heads on the-insides of the side frames provided with spherical bearmgsurfaces, horizontal struts between the opposite longrons havin their ends formed with 'saherical 1 z: 1 7

bear ng surfaces adapted to engage the- .bearing surfaces of opposite bolt heads, and wire side frames.

6. A skeleton for aircraft comprising side frames spaced apart, each side frame comprising upper and lower tubular longrons and interlongron struts or bracingmembers provided with flats at the joints, clamping plates engaging bracin between the said the flats,,fas'tening means extending through the plates the 'longrons and the interlongron struts or bracing members, said fastening means comprising bolts havingheads on the insides of the side frames provided with spherical bearing surfaces, horizontal struts between theopposite longrons ha'vingtheir structure such as a fuselage .llt)

ends formed with spherical bearing surfaces adapted to engage the spherical bearing surfaces of opposite bolt heads, wiring plates clamped between the bolt heads and the clamping plates on the insides of the side frames, and wire bracing between said side frames and connected with said wiring plates.

7. A. skeleton structure such as a fuselage for aircraft comprising side frames spaced apart, each side frame comprising upper and lower longrons and interlongron struts or bracing members the said struts or bracing members being disposed in zig-Zag girder formation between the upper and lower longerons and the said longrons and struts or bracing members being provided with flats at the joints, and the longrons being continuous through the joints, clamping plates engaging the flats, fastening means extending through the plates the longrons and the interlongron struts or bracing members, said fastening means comprising bolts having heads on the insides of the side frames adapted to engage horizontal struts I between the opposite longerons, and hor zontal struts engaged by said bolt heads.

8. A skeleton structure such as a fuselage for aircraft comprising side frames spaced apart, each side frame comprising upper and lower longrons and interlongron struts or bracing members the said struts or bracing members being disposed in Zig-zag girder formation between the upper and lower longerons and the said longrons and struts or bracing members being provided with flats at the joints, clamping plates engaging the flats, fastening means extending through the plates the longrons and the interlongron struts or bracing members, said. fastening means comprising bolts having heads on the insides of the side frames provided. with spherical bearing surfaces, liori zontal struts between the opposite longrons having their ends formed with spherical bearing surfaces adapted to engage the spherical bearing surfaces of opposite bolt heads, and wire bracing between the said side frames. I

9. A skeleton structure such as a fuselage for aircraft comprising side frames spaced apart, each side frame comprising upper and lower lengerons and interlongron struts or bracing members the said struts or bracing members being disposed in zig-Zag girder formation between the upper and lower longrons and the said long rons and struts or bracing members being provided with flats at the joints, clamping plates engaging the flats, fastening means extending through the plates the longrons and the interlongron struts or bracing members, said fastening means comprising bolts having heads on the insides of the side frames provided with spherical bearing surfaces, horizontal struts. between the opposite longrons having their ends formed with spherical bearing surfaces adapted to engage the spherical bearing surfaces of opposite bolt heads, wiring plates clamped between the bolt heads and the clamping plates on the insides of the side frames, and wire bracing between said side frames and connected with said wiring plates.

10., A skeleton structure comprising metal tubular longrons and interlongron struts er bracing members provided with flats at the joints to receive clamping plates, and the longrons being continuous through the joints, the abutting ends of said interlongron struts or bracing members being cut to abut flush against other flats on the longerons transverse to the first mentioned flats, clamping plates engaging the first mentioned flats, and fastening means extending through the plates and the interlongron struts or bracing members.

11. A skeleton structure comprising metal tubular longrons and interlongron struts or bracing members provided with flats at the joints to receive clamping plates, and the said longrons being continuous through the joints, the abutting ends of said interlongron struts or bracing members being cut to abut flush against other flats on the longrons at right angles to the first mentioned flats and against each other, clamping plates engaging the first mentioned flats, and fastening means extending through the plates and the interlongron struts or brac ing members. v

12. A skeleton structure such as a fuselage for aircraft comprising a metal tubular member, another metal tubular member with its end abutting against the first mentioned member intermediate of the ends of said first mentioned member to constitute a joint therewith, the said members being provided with flats at the joint, a clamping plate engaging the flats and fastening means extending through the plates and the tubular members meetingat the joint.

In witness whereoiv we our hands.

FREDRICK SIGRIST. SYDNEY CAMM,

have hereunto set 

